Spark-plug



A. H. CRESSY.

, SPARK PLUG. APPLICATION FILED no. 5. 19111.

1 llwem-oi ATTO R N EY WITNESSES To all whom it may concern same line as Fig.

ment.

UNITED sTATE-s PATENT OFFICE.

.ANSO1\T HENRY CRESSY, 0F HARTINGTON, NEBRASKA.

SPARK-PLUG.-

Application filed December 5. 1916." Serial No. 135.218.

' Be it known'that I, ANSON citizen of the United States, residing at Hartington, in the county of Cedar and State of Nebraska, have invented new and useful Improvements in Spark-Plugs. of which the plug and operating automatically during the different cycles of the .piston to close said combustion cavityfaga inst the 'admission of burned mixture and lubricating oil, said valve being opened by excessive pressure upon the same caused by-the ignition and expansion of explosive mixturewi'thin the combustion cavity of the plug;

lVith the above and other objects in View, the invention consists inthe novel cons-truction, combination and arrangement of parts,

herein described, illustrated and claimed.

In the accompanying drawing:

Figure l'is a diame'trical section through a spark plug embodying the present invention.

Fig. 2 is a detail perspective view ofthe valve detached. a

Fig. 3 is a fragmentary section on the of valve.

Fig. its a bottom plug embodying the valve Referring to the drawings A designates plan view ora spark generally a. sparkpl'ug of the conventional type embodying the outer shell 1,' the insulating core 2, the core clampingnl lt 3, the

central longitudinally extending power electrode t, and the electrical conductor or wire clamping nut 5, aid parts being ofthe ordinary constructlon and relative arrange- In carrying out member 6 having at its outer end a circumferential flange 7 formed at diametrlcally opposite points w lth notches 8 to receive the H. 'Cnnssv, a

provide in 1 showing another form shown in Fig. 3. r

the presentinvention, I.- employ an externally threaded, valve seat extremities of a wrench or spanner to enable said valve sea-t to be screwed into place or removed therefronfi. the inner end of the body or shell of the plug being internally threaded as shown to enable said valve seat to be screwed into and removed from.

the same. The valve seat 'is of tubular or.

hollow formation and provides in connection with the interior of the shell 1 a combus' tion cavity 9. The bore of the valve seat member isismooth and is adapted to admit of the reoiprocatory movement of the tubular stem 10.0:t a valve body 1.1, the tubular stem 10 being formed with ports 12 to allow fresh mixture to enterthe combustion cavity of the plug and the ignited mixture to expand and escape therefrom while in' a burning condition. 4

The valve body is-sh own' as provided with a conical or beveled. working face 13ivhile the'valve seat member is formed with a corresponding working face 14. The inner edge of the tubular stem of thevalve is spun or swaged outwardly to form a retaining annular lip or flange 15 which contacts with the inner extremity of the valve seat member and limits the outward or opening movement of the valve. The valve body is also formed with a diametrical niche 16 so that ,by' means of ascrew-driver, the valve may be oscillated for the purpose of grinding the Specification of Letters Patent. v Patented Aug. 19;, 1919.

working face ofthe valve body and valve,

seat. The groi'ind electrode 17 isattached to and carried by the inner face of the valve body and is shown as directly lying oppo site the extremity of the power electrode.

jThe operationof the plug in actual use may be described as follows: The valve works automatically and is controlled by and in accordance with the cycles of the piston.

'Commencing with the intake stroke of the piston, the valve opens and the combustion cavity in the plug fills with the combustion chamber of the cylinder'by the suction stroke of, the piston. During gas drawn into the compression stroke of the piston, the 2 Valve automatically closes and; remains 7 closed until thecompressiontstroke is completed, so that at the conclusion of the compression strokethere is a charge of explosivemixture in the-combustion cavity 0f theplug which is under lesscompresslon than the main charge in the cylinder. Then the explosive mixture, trapped in the combustion cavity of the plug by the automatic closing of the plug is ignited and in ex in.vthe combustion chamber of the cylinder during the firing or working strokefif said piston, the valve of the plug is again closed and remains so until the completion of the exhaust stroke of the piston. Thus the valve I serves toexclude from the combustion cavity of the plug and from the electrodes there of, oil, carbon, burned gases and other foreign matter, keeping the electrodes in perfect working condition.

In addition to the foregoing, cial efiects are described structure in a spark plug, such'efcertain spefects being based or dependent upon the Iphysical law,

which may be stated as folws: The dielectric strength of gases varies directly as the absolute pressure and inversely as the absolute temperature. Thus as the charge in the combustion cavity of the plug is under comparatively low compressionrthe spark will pass much more readily between the electrodes than it would if the electrodes were located in the main chamber or engine cylinder where it would be necessary to break down the high dielectric strength of the highly compressed main charge. Furthermore, since the valve itself forms one of the electrodes, and as the valve Wlll commence to open immediately upon ignition of the auxiliary charge in the combustion cavity of the plug, it will thereby increase the length of the gap orgsparking distance between the electrodesgand the spark will be drawn out or elongated as the dielectric strength of the-ga s between the electrodes is further lowered by the increase of temperature thereof. The described effects result in the production of a spark sufficient to ignite the chargeunderglconditions such that no spark would occur with a plug having a fixed distance orgapbetween' the electrodes, and with which the-gap is filled with portions of a highly compressed charge. I

' It will, of course, be understood that other forms of valves may be employed as well as the form illustrated. in'Figs. land 2. "F or example, a spherical or ball valve l8 may be employed as shown in Figs 3 andtand the valve seat member 19 which screws into the casing 1 may be provided with valve retaining fingers 20 to-hold the valve in place and admit of the necessary movement f said within said combustion cavity, spark passing betweensaid valve and said second electrode may ignite the chargeenobtained by the use of the principle or sacrificing any of the advantages of the invention.

I claim:

1. A spark plug having a combustion cavity in the inner portion thereof and having a' valve seat formed at the inner portion of said cavity, incombination with a valve movable toward and from said valve seat to close and open said end of the combustion cavity to entrap therein and release therefrom portions of an explosive. gaseous charge, said valve forming one electrode of the plug and a second electrode disposed trapped in said cavity and open the valve and explode the charge Within the combustion chamber ofthe engine.

- 2. Charge-igniting means for internal combustion engines, comprising aspark plug having a combustion cavity in the inner portion thereof, a valve seat formed at the inner end of said cavity, and a fixed electrode terminating in said cavity, in combination with a, valve'cooperable with said seat,

, to close said combustlon cavity, said valve being proportioned and arranged so as to be closed by gas pressure durlng the compression stroke of the piston to thereby entrap charge prior to full compression thereof,

said means movable toward and from said electrode and forming a second electrode located within the cavity whenthe' same is closed. I I

A spark plug provided with a combustion cavity and having a valve automatically operable by the pressures .in the combustion chamber or. engine and adapted to confine a charge of explosive mixture within the said cavity on the compression strok of the engine and means carried by the spark cause the i nited-charge to .open the valve and ignite the-charge within the combustion chamber of the engine.

In testimony whereof I afiix my signature.

ANSDN HENRY CRES-S Y.

plug 'for ign ting the charge. witnm 1ts cavity to whereby a 

